What Is An Impact Driver?

The Impact Driver is a very popular and versatile tool, not dissimilar to the general purpose Drill Driver. However the Impact Driver can generate nearly 3 times as much torque!

Impact Drivers are specifically designed to automatically overcome resistance encountered when driving. The user no longer has to apply extra force, as when using regular drills and Drill Drivers.

The Impact Driver is used where power is more important than precision.

It is great for driving larger screws and fasteners into harder wood, masonry and even sheet rock.

Large screws can be secured 3 times faster than with a Drill Driver, and with much less effort.

It is also perfect for tightening or loosening rusted bolts.

What Does An Impact Driver Look Like?

Impact Drivers look like cordless Drill Drivers but they are smaller, lighter and have a more compact profile.

Their shorter nose is due to the fact they don’t have a standard keyed or keyless chuck.

Instead they have a ¼” quick release locking collet into which you simply slot a hexagonal shank bit after pushing down on the collet ring.

They also have no torque control ring (this will be explained later on).

Also their motors are smaller than regular power drill motors because more power is generated by the impact motion itself.

Therefore smaller batteries can be used to power those smaller motors.

As per Drill Drivers Impact Drivers can come as bare tools, or with stick or slotted batteries.

The compact profile, stubby nose and lack of torque control ring on the Impact Driver makes it quite distinct from the Drill Driver.

What Is An Impact Driver Used For?

Impact Drivers are not only smaller and lighter than Drill Drivers but they are also much more powerful. So where would you use one?

Well if you are considering any sort of construction or home improvement project read on!

As we said in the introduction they are great for driving larger screws, fasteners and bolts into less forgiving materials like harder wood, masonry and stone.

These are the tasks that would flatten your battery in minutes if you were using a regular Drill Driver!

So if you are building a deck or doing studwork, securing a timber frame, screwing down plywood or floorboard, hanging cabinets or driving into masonry then this is the tool of choice.

It is also great for tightening or loosening rusted bolts, nuts or screws in wood or metal.

Just ensure you use specialist Impact Driver bits for these tasks since standard bits will quickly fail with the increased levels of impact applied.

Although not specifically designed for drilling holes, you can increase the Impact Driver’s versatility by adding a drill chuck adaptor.

This is a separate chuck with a spindle converted into a hexagonal shank that slots into the impact driver collet. It now allows the Impact Driver to use standard bits and any other accessory with a round shank.

A good example is using a spade bit for drilling large holes in lumber.

All in all a very useful tool to have at your disposal!

How Does An Impact Driver Work?

The key feature of the Impact Driver is its ability when driving to detect resistance and automatically apply an extra proportional level of impact (hence its name) or torque to overcome it.

It is important to note that the user has no control over when this extra force is applied, and therefore torque control rings /settings are not present on Impact Drivers.

When resistance is detected the motor engages a hammer which in turn strikes an anvil in the same direction the motor is turning.

These hammer blows or impulses are delivered at lightning speed, up to 3,000 beats per minute, in order to apply the extra rotational force or torque required to overcome the resistance.

When there is no more resistance the hammer anvil action stops, but the cycle will restart if further resistance is encountered.

The other great feature of this mechanism is that you don’t get kickback.

When Rotary Drills or Drill Drivers encounter resistance the drill bit can sometimes get stuck.

When this happens the rotational force can be transferred from the drill bit back to the drill itself.

If the drill bit is still tight in the chuck, the unwanted force can trigger back to the user, causing the whole drill to spin and possible injury to wrists and hands.

What Impact Driver Main Features And Specifications Should I Be Looking For?

There are not that many differences between Impact Driver models and brands.

They are all relatively lightweight, have a ¼” collet and can deliver around 3,000 bpm (beats /impacts per minute).

No-load speed is around 3,000 rpm and max torque ratings around 1,500 inch lbs, around 3 times that of a Drill Driver.

More expensive models may have more than one gear or a brushless motor but these are in no way essential.

Try and go for one with a Lithium-Ion battery – most are equipped with these anyhow – 18 volts is the most popular.

Although there is no torque ring, some do come with an integrated clutch. This is useful because it can be engaged if you think you are going to over tighten a screw on account of the higher torque being delivered.

Be aware though this is quite a noisy tool!

Impact Driver Variations

Impact Wrenches are similar to Impact Drivers. They too are designed to overcome resistance but they are designed to work in a twisting or horizontal mode, as opposed to Impact Drivers that apply force vertically.

Therefore Impact Wrenches are ideal for tightening and loosening bolts.

What Shouldn’t An Impact Driver Be Used For?

It should hopefully be clear that the Impact Driver is a powerful tool and should not be used for delicate tasks, primarily because you cannot control exactly when the torque surges kick in.

So don’t use it for self-assembly furniture, tightening smaller screws into metal or anywhere you want to drill precise holes.

You may not get the clean finish you desire, so use your Drill Driver for those tasks instead!

Neither should the Impact Driver be used as a hammer drill. The percussion action on a Hammer Drill is applied vertically and constantly with added force by the user, whilst Impact Driver action is applied sideways, irregularly (when extra resistance is met) and automatically.

How Much Does An Impact Driver Cost?

An Impact Driver costs significantly more than a Drill Driver with an equivalent specification. A lot are sold as bare tools and if you were to add in the cost of a battery even the cheaper alternatives will set you back close to £100.

Manufacturers regularly package Impact Drivers in “combo” with Drill Drivers, significantly discounting the price of the 2 individual drills, something to be considered if you need both tools.